Communication Theory Notes and Study Material PDF Free Download

Communication Theory Notes: Communication is the essence of life. It is the process by which we share information. The technical study of the process of information is called Information theory. Primarily it is a field of information theory and mathematics. It also studies different forms of communication, like interpersonal and intrapersonal communication. It is also used in the studies of psychology, sociology and anthropology.

When we study communication theory, the most important aspect is how communication takes place. The three most common models of communication are the Linear Model, Interactional model and Transactional model. There are certain basic elements of communication that we study about when we study communication theory. It talks about how information from the source which contains the message reaches the receiver. Students can refer to the Big Data Lecture Notes For CSE as per the latest and updated syllabus from this article.

You can find your free notes pdf here. These notes are reliable and accurate. Plus these are regularly updated to incorporate any changes in the course module which makes them the most up-to-date available online. For further details click on any of the links below.

Communication Theory Notes PDF Download

Communication theory notes pdf available for download is one of the most sought after study material online. This pdf is reliable and accurate as experts verify them. Also, this pdf is recommended by teachers and students alike. Students in the 4th semester can use this pdf in their preparations for their exams. Communication theory revolves around some basic concepts and to have sound knowledge of these concepts you can consult the free pdf available. The language used in the pdf is simple to understand so that students can learn the topic well.

This pdf is available for download free of cost. You can download it using the links given below and start your preparations. It also contains links to additional study material. Students can use these to their advantage in their preparations for their final exams and perform better.

  • Communication theory Notes Pdf download.
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  • Communication theory 4th-semester pdf
  • Notes for communication theory free pdf
  • Sample questions Communication theory
  • Previous years question papers Communication theory pdf.

Reference books for Communication Theory

Finding the right book in this information-rich age can be a daunting task. There are many free e-books available online you can use for your preparations. Many more are available in the market for your reading. Whenever you need a good and accurate reference book, always go for writers that are recommended by your teachers and your seniors. Also, look if the latest edition of the book is available, which suggests that the book is being updated from time to time to include all the improvements and changes in the syllabus if any.

Given below is a list of suggested reading verified by experts in the field. These are the most recommended books by teachers and students. The list is in no particular order, and you can consult any of these during your preparations. It is advisable to look for newer editions of these books if available.

  • Communication theory, David Holmes(2005)
  • J.G.Proakis, M.Salehi, “Fundamentals of Communication Systems”, Pearson Education 2006.
  • Encyclopedia of Communication Theory, Karen A. Foss (2009)
  • Communication Theory, J.S. Chitode (2007)
  • Communication theory and research (2005)
  • Understanding Communication theory: A beginner’s guide, Stephen Micahel Croucher(2015)
  • Introducing communication theory: Analysis and application
  • An introduction to analog and digital communication, 2nd edition
  • Mass Communication theory: Foundations, ferment and future, by Stanley J. Baran & Dennis K. Davis, 6th edition (2011)
  • S. Haykin, “Digital Communications”, John Wiley, 2005.
  • A first look at communication theory, Griffin Em(1991)

Communication Theory Syllabus

Communication theory is an important paper in the 4th semester. Students need to be aware of the syllabus so that they can plan their preparations for the exams. This paper tests both the theoretical and practical knowledge of the students and the syllabus is split up into different modules. Each unit is important from an exam point of view, and students should give equal weightage to every unit and chapter because everything here is interlinked.

The entire communication theory syllabus is divided into five units to introduce students with the basics of communication theory, understand the basic concepts of modulation, to study noise and its effect on communication systems. The course contents are:

Unit 1: AMPLITUDE MODULATION Amplitude Modulation- DSB SC, DSBFC, SSB, VSB – Modulation index, Spectra, Power relations and Bandwidth – AM Generation – Square law and Switching modulator, DSB SC Generation –Balanced and Ring Modulator, SSB Generation – Filter, Phase Shift and Third Methods, VSB Generation – Filter Method, Hilbert Transform, Pre-envelope & complex envelope –comparison of different AM techniques, Superheterodyne Receiver.
Unit 2: ANGLE MODULATION Phase and frequency modulation-Narrow Band and Wind band FM – Spectrum – FM modulation and demodulation – FM Discriminator- PLL as FM Demodulator – Transmission bandwidth.
Unit 3: RANDOM PROCESSES Random variables, Central Limit Theorem, Random Process, Stationary Processes, Mean, Correlation & Covariance functions, Power Spectral Density, Ergodic Processes, Gaussian Process, Transmission of a Random Process Through an LTI filter.
Unit 4: NOISE CHARACTERIZATION Noise sources and types – Noise figure and noise temperature – Noise in cascaded systems. Narrowband noise – PSD of in-phase and quadrature noise –Noise performance in AM systems – Noise performance in FM systems – Pre-emphasis and de-emphasis – Capture effect, threshold effect.
Unit 5: SAMPLING AND QUANTIZATION Entropy – Discrete Memoryless channels – Channel Capacity -Hartley – Shannon law – Source coding theorem – Huffman & Shannon.

Theoretical problems for Communication Theory

Communication Here is a list of common questions related to Communication theory. These are all very fundamental questions to lay the foundation of what’s to be expected from the course. Students are advised to go through these questions if you are preparing for your exams or thinking to sit for a job interview as these are some commonly asked interview questions as well.

  1. Mention the advantages of modulating low-frequency signal to a high-frequency signal.
  2. List the type of AM modulators.
  3. Why do you need modulation in communication systems?
  4. Explain amplitude modulation.
  5. What is frequency modulation?
  6. What do you understand by phase modulation?
  7. What are the different types of communication?
  8. Explain different models of communication.
  9. Differentiate between amplitude modulation and frequency modulation.
  10. What is the base station?
  11. What do you understand by attenuation?
  12. Explain full-duplex and half-duplex.
  13. What are the advantages of negative feedback over positive feedback?
  14. What is an Amplifier?
  15. Explain the working of an oscillator.
  16. What is a rectifier?
  17. How many satellites can cover the entire earth?

Frequently Asked Questions on Communication Theory Notes

Question 1.
Explain feedback. What are the different types of feedback?

The process by which a certain proportion of the output signal is fed back into the input of the system. It is used in preserving and controlling the dynamic behaviour of the signal. During communication, when we send messages, we observe feedback. This feedback received is not in terms of the message from the receiver but rather a mathematical notation.

Negative feedback: Negative feedback takes the system towards an equilibrium state. The signal fed is out of phase ( by 180°) to the input signal or is of opposite polarity. Negative feedback is used in amplifiers. It attenuates the fluctuations, and that is why it finds application in sound systems.

Positive feedback: Positive feedback takes the system away from the equilibrium state. The signal fed back into the system is in the phase of the input signal or of the same polarity. Positive feedback is used in oscillators.

Question 2.
Differentiate between Analog and Digital Communication.

There are two types of communication. These are:

Analog Communication: The data is transmitted with the help of an analog signal. It is converted into electric signals and then transmitted over the distance. It uses a continuous signal which varies in amplitude, phase or frequency.

Digital communication: The data is transmitted with the help of digital signals which consists of discrete values rather than continuous signals. It can be broken down into smaller pieces as discrete messages.

Analog Communication Digital Communication
It is a continuous signal where amplitude, phase or frequency change with time. It is made up of discrete values, i.e. 1 and 0
Affected by noise during transmission  Not much affected by noise during transmission.
The number of channels that can be broadcasted is limited. The number of channels that can be broadcasted is unlimited.
It requires low bandwidth. It requires high bandwidth.
It is more complex and less flexible. It is comparatively, simpler and flexible.
System cost is low System cost is high
Data transmitted is less accurate. Accurate data transmission

Question 3.
Explain Amplitude modulation.

This process is defined as amplitude modulation. It is defined as the process of increasing the strength (amplitude) of the signal with the help of a carrier wave with the same frequency and different amplitude in accordance with the audio signal. This modulated signal is demodulated at the receiver’s end using a demodulator which gives back the original signal wave without any decrease or interference in the signal.

The need for modulation arises due to

  • A higher range of transmission
  • Improving the quality of transmission over longer distances
  • To avoid interference of audio signals.

The mathematical representation of the amplitude-modulated wave is:

s(t)= amplitude modulated wave
Am= amplitude of the modulating signal
fm=frequency of the modulating signal
Ac= amplitude of the carrier wave
fc= frequency of the carrier signal

Question 4. 
Explain different models of communication.

Communication is the process of sending, receiving and interpreting messages. The three most common models of communication are as follows:

The linear model of communication – It is the most simple form of communication where the sender sends the message to the receiver using a simple transmitter. It was commonly used during earlier times, but its use was very limited because communication is not linear.

Interactional model – It is a mode of communication which allows back and forth transmission of messages. It resembles communication more because it includes feedback. Here the sender sends the message and receives the feedback.

Transactional model – It is the most commonly used mode of communication. It depicts communication in the modern age. It has no sender or receiver, but rather people involved are referred to as communicators.


Communication theory revolves around some basic concepts. If these concepts are clear students will find this subject interesting as well as scoring. Students are advised to go through the communication theory notes pdf to get reliable and accurate information about topics,c concepts and applications. The pdf is really helpful for 4th-semester students in their preparations for their semester end exam. You can download the free download here and start your preparations.

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